Interactions

Interactions with Drugs

Marijuana may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Marijuana may affect blood sugar levels. Caution is advised when using medications that may also affect blood sugar. People taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.

Marijuana may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be increased in the blood and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Marijuana may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.

Interactions with Herbs and Dietary Supplements

Marijuana may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Marijuana may affect blood sugar levels. Caution is advised when using herbs or supplements that may also affect blood sugar. Blood sugar levels may require monitoring, and doses may need adjustment.

Marijuana may cause low blood pressure. Caution is advised in people taking herbs or supplements that lower blood pressure.

Marijuana may interfere with the way the body processes certain herbs or supplements using the liver's cytochrome P450 enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.

Marijuana may increase the amount of drowsiness caused by some herbs or supplements.

Marijuana may also interact with anabolic steroids, anticancer herbs and supplements, antioxidants, antiseizure herbs and supplements, barbiturates, benzodiazepines, central nervous system depressants, corticosteroids, dopamine antagonists, fertility herbs and supplements, herbs and supplements that may affect blood vessel width, herbs and supplements that may affect the immune system, herbs and supplements that may be toxic to the liver, herbs and supplements that may improve breathing or treat lung disorders, herbs and supplements that may increase appetite, herbs and supplements that may treat heart disorders, herbs and supplements that may treat nausea and vomiting, herbs and supplements that may treat nervous system disorders, herbs and supplements that may treat psychiatric disorders, herbs and supplements that may treat retrovirus infections (HIV), herbs and supplements that may treat skin disorders, herbs and supplements that may treat stomach disorders, hormonal herbs and supplements, nicotine, nonsteroidal anti-inflammatories, opioid receptor antagonists, pain relievers, p-glycoprotein-regulated herbs and supplements, phytoestrogens, and synthetic cannabinoids.